Narcolepsy: What Exactly Is It?

Imagine falling asleep while driving, without warning or time to pull over. Imagine fighting such uncontrolled sleepiness in the day that it’s hard to function at work or home. You’re not sure when you’ll conk out in the middle of eating or talking.

Such is the life of an individual with narcolepsy, a chronic neurological disorder that interferes with our brain’s regulation of the sleep-wake cycle.  

“Although not very common, narcolepsy is not rare,” says Salim Dib, M.D., a neurologist at the University of Miami Health System who specializes in sleep disorders. “It’s also very difficult to diagnose. It takes an average of about 10 years from symptom onset for a person to get a diagnosis.”

About 1 in every 2,000 people suffer from the condition, or about 200,000 Americans and 3 million worldwide, according to the Narcolepsy Network. That number, however, might be on the low side. Experts estimate that only 25% of people who have narcolepsy are actually diagnosed.

Many of narcolepsy’s symptoms mimic other conditions.

Dr. Dib says that individuals with the condition are often initially misdiagnosed. In fact, a recent study put that figure at 60%.

It’s not unusual for patients to be misdiagnosed with depression, obstructive sleep apnea, or insomnia.

Most of Dr. Dib’s patients are referred to him by other health care providers.

Most, too, are frustrated that treatment for other conditions hasn’t helped them. By the time they arrive at his clinic, they are desperate for answers.

One of his patients, a young woman, is a good example. She had undergone several expensive evaluations after repeatedly falling asleep in school or missing class altogether. On a few occasions, she had suffered through sleep paralysis, a temporary inability to move when waking up or falling asleep. Though an episode may only last a few seconds, sleep paralysis can be quite frightening. She also reported very vivid dreams, both at night and during her daytime naps, and she sometimes found it hard to distinguish them from reality.

As her symptoms deepened, the young woman stopped going to school and withdrew from her social life. She was diagnosed with depression, but medication provided no relief. Finally, a second psychiatrist referred her to the sleep clinic, where she was diagnosed with narcolepsy — and her reaction was typical of other patients.

“Because it takes a few years to get an answer, patients are actually relieved to know what they have,” Dr. Dib says.

Even when we explain that there is no cure [for narcolepsy] and that it’s chronic, it’s not going away, they finally have an answer for why this is happening.
– Salim Dib, M.D.

Individuals with narcolepsy experience fragmented sleep during the night.

This, however, is not the cause of excessive daytime sleepiness that can lead to sudden but short “sleep attacks,” when a person falls asleep in the middle of doing something, usually a habitual activity like driving or eating.  Researchers have discovered that most cases of narcolepsy are caused by the loss of hypocretin neurons in the hypothalamus, a small area of the brain that regulates not only our sleep but our metabolism in general.

There are two kinds of narcolepsy. 

Patients with Type 1 have low levels of hypocretin in the Cerebrospinal Fluid (CSF) and/or cataplexy, which is an unexpected loss of muscle control during waking hours. Cataplexy can be triggered by emotions, from stress to fear but also excitement. Some patients may have only a couple of attacks in their lifetime, but some can suffer from several a day. The severity of the attacks can also vary greatly. They can range from mild (a slack jaw, a droopy eye) to extreme (full body collapse).

In Type 2 narcolepsy, patients still suffer from excessive daytime sleepiness but not cataplexy. They also have normal levels of hypocretin in the CSF and less acute symptoms.

While it may still be under debate, many researchers in the field believe that “most cases of narcolepsy start as an autoimmune disorder, when a patient’s immune system attacks the brain cells that contain hypocretin neurons,” Dr. Dib says. This attack may result from a combination of environmental and genetic factors that trigger the symptoms in those who already are predisposed to the condition.

Researchers have also discovered a genetic marker for narcolepsy.

About 25% percent of the population has that gene, but of those a minuscule 0.2 percent go on to develop narcolepsy.

While most patients are diagnosed in adolescence or as young adults, the onset of narcolepsy can also occur in older adults. In those cases, “we see people who suffer from other kinds of autoimmune or inflammatory disorders,” says Dr. Dib. In other words, individuals who have conditions like multiple sclerosis or lupus.  In rare cases, some who have suffered a stroke are at risk of developing narcolepsy.

Diagnosing narcolepsy is a multi-step process.

First, Dr. Dib asks prospective patients to keep a sleep diary to track sleep duration and symptoms. He will also take a medical history and conduct a physical exam to rule out other potential causes including other sleep disorders.

Tests are also required for a diagnosis.

One of them is a polysomnogram (PSG), or what is commonly referred to as an overnight sleep study, which records breathing, eye movements, and brain and muscle activity.

Another test, the multiple sleep latency test, measures how quickly a person falls asleep and slips into REM sleep, a stage of sleep most closely associated with dreaming.  Patients with narcolepsy usually enter REM sleep very quickly, within 15 minutes during their naps. Lastly, if necessary, a sleep doctor may measure hypocretin levels in the cerebrospinal fluid during a spinal tap.

In the end, says Dr. Dib, “clinical supposition is key once we exclude other possible causes.”

Treatment is typically a stepwise approach, starting with lifestyle changes, often in combination with wake-promoting medications and stimulants . Certain antidepressants can also help with cataplexy, as does sodium oxybate.

Patients can see relief within a few weeks if they tolerate the drugs well.

“We give them hope,” Dr. Dib says.  “Although the treatment may not be a cure, one can return to a normal active lifestyle. So many patients say it [the treatment] made all the difference between being disabled and regaining functional ability.”

In the case of his young female patient, medication has allowed her to return to school and socialize. She told him, “You gave me my life back.”

Ana Veciana-Suarez is a regular contributor to the University of Miami Health System. She is an acclaimed author and journalist who has worked at The Miami Herald, The Miami News, and The Palm Beach Post.

Tags: Chronic neurological disorder, Dr. Salim Dib, Narcolepsy symptoms, neurology care in Miami, Sleep attacks